Joel Davison's bloghttp://www.cd-adapco.com/blogs/joel-davison
enhttp://www.cd-adapco.com/node/7629
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p dir="ltr">Recently I reached my ten year anniversary working for CD-adpaco and it got me to thinking about how far CAE has come in that time, specifically in the field of meshing. I “grew up” in a world where meshing was closer to art than science and generating a mesh often required days of manual work and lots of head scratching. If at the end of this, you ran your solution and found your mesh missed critical flow features you had to go through the whole process again (after you had finished bashing your head against your CRT monitor that is).</p>
<p dir="ltr"><span>With the advent of STAR-CCM+, and its innovative meshing pipeline, this all changed and suddenly generating meshes and most importantly changing those meshes was quick and easy. In v10.02, we have a new feature to augment these capabilities to help you to not only build your meshes more easily, but more intelligently. The tool I’m talking about here is Adjoint error estimation which leverages the power of adjoint to highlight discretization errors in your mesh that may be due to inappropriately sized and distributed cells. These discretization errors may, in turn, affect the accuracy of your engineering results.</span></p>
<p dir="ltr"><span>Run after your initial simulation, the adjoint error estimation presents you with a field that shows where in your mesh the greatest error is with respect to your cost functions. You can use this field to then refine or coarsen your mesh using table refinements to minimize this error and so improve your accuracy and confidence in your results.</span></p>
<p dir="ltr"><span><img src="/sites/default/files/Error_Mag1.png" alt="Adoint error estimation behind aerofoil STAR-CCM+" width="500" height="265" style="margin: 5px; vertical-align: middle;" /></span></p>
<p dir="ltr"><span>In the example above, the field shows the errors affecting the drag of my airfoil</span></p>
<p dir="ltr"><span>The benefit here is that you can create a mesh that is more efficiently structured to reduce error in your solution. By placing refinements only where needed it means you don’t waste cells refining in areas that have little impact on your solution and accordingly produce a mesh that requires less computational effort to produce the desired levels of accuracy. So not only do you benefit from a more accurate result but that accuracy does not have to come at the cost of a greatly increased mesh size and so, potentially, a longer run time.</span></p>
<p><span id="docs-internal-guid-3cdb31cf-595a-ca21-bd62-45e93af43857"><span>Luckily CRT monitors are a thing of the past and so too is banging your head against them in frustration and building the wrong mesh. With the new adjoint based error estimation feature we really take the stressing out of meshing!</span></span></p>
<p dir="ltr"><span><img src="/sites/default/files/Coarse_Filled_Mesh.png" alt="Coarse mesh results" width="500" height="265" style="vertical-align: middle; margin: 5px;" /></span></p>
<p><span><span><span id="docs-internal-guid-3cdb31cf-595c-a902-534b-8f6aedb276fd"><span><img src="/sites/default/files/Fine_Filled_Mesh.png" alt="Fine mesh results" width="500" height="265" style="vertical-align: middle; margin: 5px;" /></span></span></span></span></p>
</div></div></div><div class="field field-name-field-products field-type-taxonomy-term-reference field-label-above"><div class="field-label">Products:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/products/star-ccm%C2%AE" typeof="skos:Concept" property="rdfs:label skos:prefLabel">STAR-CCM+®</a></div><div class="field-item odd"><a href="/products/technologies" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Technologies</a></div><div class="field-item even"><a href="/products/star-ccm%C2%AE/advanced-meshing" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Advanced Meshing</a></div></div></div>Thu, 05 Feb 2015 11:02:12 +0000Joel Davison7629 at http://www.cd-adapco.comSTAR-CCM+ v9.06 Preview: Enhanced Mesh Morphing Capabilitieshttp://www.cd-adapco.com/blog/joel-davison/star-ccm-v906-preview-enhanced-mesh-morphing-capabilities
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p dir="ltr"><span>In my last </span><a href="http://www.cd-adapco.com/blog/joel-davison/star-ccm-v904-cad-robustness-and-adjoint-expressions"><span>blog </span></a><span>I spoke about some of the improvements to our design exploration tools. For version 9.06 of <span class="hiddenSpellError">STAR-CCM</span>+, we have worked on another facet of design exploration, by improving <span class="hiddenGrammarError">the usability of</span> our mesh <span class="hiddenSpellError">morpher</span> which allows you to more easily <span class="hiddenSuggestion">perform</span> free-form, non-parametric, deformation of your geometry.</span></p>
<p dir="ltr"><span>At the beginning of the year we released the mesh deformation model which enabled you to change the shape of your geometry using <span class="hiddenSpellError">morpher</span>. This is an important <span class="hiddenSuggestion">capability</span> as you may not always have access to the raw CAD data, or indeed the software required to <span class="hiddenSuggestion">modify</span> it.</span> </p>
<p dir="ltr"><span>In v9.06 we have introduced a set of tools to create, visualize and <span class="hiddenSuggestion">modify</span> the control points used to deform your geometry. Previously these points had <span class="hiddenGrammarError">to be</span> specified in a table but now you can easily create them interactively as lines and lattices of points or offset from the vertices on the surface of your mesh. This allows you to place your points more effectively to <span class="hiddenSuggestion">perform</span> the design changes you <span class="hiddenSuggestion">require</span>. </span></p>
<p><span><img src="/sites/default/files/jbd1_0.png" alt="Control points illustrate potential improvements" width="500" height="294" style="margin: 5px;" /> </span></p>
<p style="text-align: center;" dir="ltr"><strong>You can now easily create and visualize control points as lines, lattices or from mesh vertices to morph your geometry and <span class="hiddenSuggestion">perform</span> design changes</strong></p>
<p dir="ltr">The real power of the control point tools <span class="hiddenGrammarError">is realized</span> when you leverage <span class="hiddenSpellError">adjoint</span> to <span class="hiddenSuggestion">perform</span> sensitivity studies. The <span class="hiddenSpellError">adjoint</span> solver uses the <span class="hiddenSpellError">morpher</span> to <span class="hiddenSuggestion">provide</span> information on how moving your control points will affect your result. So, <span class="hiddenSuggestion">for example</span>, if you want to <span class="hiddenSuggestion">reduce</span> the pressure drop of your system, you can place control points within your geometry and then run an <span class="hiddenSpellError">adjoint</span> analysis. The <span class="hiddenSpellError">adjoint</span> results will then tell you how moving each of the points will affect your pressure drop so you can easily deform your shape to improve the system’s performance.</p>
<p dir="ltr"><span>The control points may also display this <span class="hiddenSuggestion">position</span> information visually using post-processing scenes, this allows you to place your control points around your geometry and see which areas will have the most effect on your cost function. So, to take another example, if you are designing a car and wish to improve its aerodynamic performance, you can use the control points, coupled with the <span class="hiddenSpellError">adjoint</span> solver, to show you the areas of the body that have the greatest effect on your drag. You can then <span class="hiddenSuggestion">focus in</span> on these areas for improvement or use the information to guide you in which <span class="hiddenSuggestion">parameters</span> to <span class="hiddenSuggestion">modify</span> in a parametric design exploration using <span class="hiddenSpellError">STAR-CCM</span>+ /Enabling <span class="hiddenSpellError">Optimate</span>+. </span></p>
<p><span> <img src="/sites/default/files/jbd2_0.png" alt="Vectors illustrate the direction of surface perturbations that might improve the desigh " width="500" height="294" style="margin: 5px; vertical-align: middle;" /></span></p>
<p style="text-align: center;" dir="ltr"><strong>By using control points with the <span class="hiddenSpellError">adjoint</span> solver you can easily visualize the potential effects of geometry changes</strong></p>
<p> <span> <img src="/sites/default/files/JBD3_0.png" alt="Optimization of rear wing design leads to improvements" width="500" height="293" style="margin: 5px; vertical-align: middle;" /></span></p>
<p style="text-align: center;" dir="ltr"><strong>In the example above the control point tool was use to improve the aerodynamic performance of the car by morphing the rear wing to improve downforce/drag</strong></p>
<p><span> </span></p>
</div></div></div><div class="field field-name-field-industries field-type-taxonomy-term-reference field-label-above"><div class="field-label">Industries:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/industries/ground-transportation" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Ground Transportation</a></div><div class="field-item odd"><a href="/industries/ground-transportation-application" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Ground Transportation - Application</a></div><div class="field-item even"><a href="/industries/ground-transportation/%E7%A9%BA%E6%B0%94%E5%8A%A8%E5%8A%9B%E5%AD%A6" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Aerodynamics</a></div></div></div><div class="field field-name-field-products field-type-taxonomy-term-reference field-label-above"><div class="field-label">Products:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/products/star-ccm%C2%AE" typeof="skos:Concept" property="rdfs:label skos:prefLabel">STAR-CCM+®</a></div></div></div>Tue, 07 Oct 2014 10:38:27 +0000Joel Davison7367 at http://www.cd-adapco.comSTAR-CCM+ v9.04: CAD Robustness and Adjoint expressions http://www.cd-adapco.com/blog/joel-davison/star-ccm-v904-cad-robustness-and-adjoint-expressions
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p dir="ltr"><span>During the opening session of the </span><a href="http://www.cd-adapco.com/blog/stephen-ferguson/simulating-systems-sgc14-highlights"><span>STAR Global Conference</span></a><span> earlier this year, Didier Halbronn, CD-adapco Vice President of European Sales, spoke about our ongoing commitment in the field of multi-disciplinary design exploration (MDX). In this blog I want to highlight a couple of new features in v9.04 of STAR-CCM+ that approach this in different ways.</span></p>
<h2 dir="ltr"><span>Ensuring Robust CAD</span></h2>
<p dir="ltr"><span>One of the challenges of parametric optimization is ensuring that the CAD model is tolerant to the full range of variations that the product is likely to encounter (both in its operational life and during the optimization process). As model sophistication grows and parameters may become interrelated, it is hard to know up front how robust your model is to variation and how many regeneration failures you may have. </span></p>
<p dir="ltr"><span>Too many CAD regeneration failures and you can’t have confidence that you design truly is the optimum or that the relationships between inputs and outputs in your DOE are valid. While the CAD regeneration step is usually short, the simulation that follows it may be more time consuming and if you don’t have confidence in the result due to the number of failures, a lot of time may be wasted. </span></p>
<p dir="ltr"><span>To alleviate this issue, v9.04 of STAR-CCM+ /Enabling Optimate and Optimate+ has the option to perform a CAD robustness study. This study, performed before the full analysis, allows you to quickly check the robustness of your design ensuring that time isn’t wasted performing simulations that may be wasted due to failed geometry regeneration. Not only does it save you time, it also gives you confidence that you can truly find better designs faster.</span></p>
<p dir="ltr"><span><img src="/sites/default/files/inhalersmall_0.gif" alt="CFD optimization CFD " width="500" height="360" style="margin: 5px;" /></span></p>
<p dir="ltr"> </p>
<h2 dir="ltr"><span>Tying Objectives Together</span></h2>
<p dir="ltr"><span>While STAR-CCM+ /Enabling Optimate+ provides a compelling solution for parametric optimization and sensitivity analysis it is not the only tool we have for MDx. For non-parametric studies, where geometry modification is not constrained by a CAD model, the STAR-CCM+ adjoint solver is a powerful method for exploring your design space in a more free-form way. </span></p>
<p dir="ltr"><span>The </span><a href="http://www.cd-adapco.com/webinar/using-adjoint-solver-gain-greater-insight-product-behavior"><span>adjoint solver</span></a><span> gives you information about how changing the shape, flow field and boundary conditions for your design will affect your cost functions, which represent your engineering objectives. In common with parametric optimization, you will often want to look at a combination of different objectives and how sensitive they are to your design. From STAR-CCM+ v9.04 onwards this is now possible with adjoint as well. </span></p>
<p><span><img src="/sites/default/files/ComparisonPlots_20566_image001.png" alt="CFD Lift and Drag wing profile optimization" width="500" height="328" style="vertical-align: middle; margin: 5px;" /> </span></p>
</div></div></div><div class="field field-name-field-products field-type-taxonomy-term-reference field-label-above"><div class="field-label">Products:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/products/star-ccm%C2%AE" typeof="skos:Concept" property="rdfs:label skos:prefLabel">STAR-CCM+®</a></div><div class="field-item odd"><a href="/products/add-ons" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Add-ons</a></div><div class="field-item even"><a href="/products/star-ccm%C2%AE/optimate%E2%84%A2" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Optimate™</a></div><div class="field-item odd"><a href="/products/technologies" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Technologies</a></div><div class="field-item even"><a href="/products/star-ccm%C2%AE/automation" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Automation</a></div><div class="field-item odd"><a href="/products/workflow" typeof="skos:Concept" property="rdfs:label skos:prefLabel">Workflow</a></div><div class="field-item even"><a href="/products/star-ccm%C2%AE/cad-mesh" typeof="skos:Concept" property="rdfs:label skos:prefLabel">CAD to Mesh</a></div></div></div>Tue, 24 Jun 2014 10:53:47 +0000Joel Davison6999 at http://www.cd-adapco.comSTAR-CCM+ v9.02: Adjoint Tumble and Swirlhttp://www.cd-adapco.com/blog/joel-davison/star-ccm-v902-adjoint-tumble-and-swirl
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p dir="ltr"><span>One of the greatest challenges of engineering analysis is the ability to understand how changes in geometry and flow features might influence your system’s performance. For a long time, the only way to gain insight into the sensitivity of engineering objectives to changes in input was to run multiple analyses and then dig through the results. The introduction of the adjoint solver in STAR-CCM+ v8.04, however, changed that - allowing for direct access to sensitivity information from a single simulation.</span></p>
<p>In the upcoming version of STAR-CCM+, v9.02, we have a number of new features that broadens the applicability and improves the ease of use of the adjoint solver. Chief among these developments is the new tumble and swirl cost function -a feature implemented based on direct feedback from our industrial users. This cost function, targeted at the IC engine community, allows for sensitivities to be presented with respect to a key metric used in steady-state port flow analyses. In such studies, improving the tumble and swirl characteristics of the port is critical, so the additional insight that the adjoint solver brings will be of great benefit.</p>
<p>To improve ease of use, the adjoint cost functions have been migrated to STAR-CCM+’s standard reporting capability. This allows you to understand whether the cost functions you are interested in are returning sensible values before you run the adjoint solver itself. The reports themselves are available, regardless of whether you are interested in adjoint or not. This means all users can benefit from the new tumble &amp; swirl report, as well as the addition of a pressure drop and uniformity deviation report.</p>
<p>STAR-CCM+’s adjoint solver has already come a long way since it’s first release just eight short months ago and the pace of development will continue. We believe it’s a technology that can benefit all of our users and so we continue to be committed to its future development with a dedicated team improving and enhancing the tool. There are a lot of exciting new features coming with v9.02 and beyond. I hope you get a chance to try them out and let us know what you think.<img src="/sites/default/files/body_images/user279/heart-thingy.jpg" alt="Tumble and Swirl Adjoint Solver" title="Tumble and Swirl Adjoint Solver - Simulation Image" width="500" height="327" style="margin: 15px 0px;" /></p>
<p><span> </span></p>
</div></div></div>Tue, 18 Feb 2014 20:09:37 +0000Joel Davison6571 at http://www.cd-adapco.comSTAR-CCM+ v8.06 preview: Introducing the Simulation Assistanthttp://www.cd-adapco.com/blog/joel-davison/star-ccm-v806-preview-introducing-simulation-assistant
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even" property="content:encoded"><p>Once upon a time, you might have been the only simulation engineer in your company. If you weren't working alone then you were probably part of a small team. Consistency and 'best practices' were never a problem, because in a small group of engineers you could easily look over each others shoulders, and discuss model settings and assumptions by the water cooler.</p>
<p>However, as simulation has become a more important part of the engineering process, simulation teams have grown bigger and more geographically dispersed. The sheer volume of simulation being performed in product development makes it increasingly difficult (or probably impossible) for any single person to keep a handle on all of the simulation work that is going on inside an organization. You might not even know all of the other simulation engineers working on your project.</p>
<p><img src="/sites/default/files/iStock_000009058764Large.jpg" alt="Introducing the Simulation Assistant" width="500" height="228" style="vertical-align: middle; margin: 5px;" /></p>
<p>The danger here is that, what we gain in productivity, we lose in consistency and repeatability. <a href="http://www.cd-adapco.com/blog/stephen-ferguson/art-and-science-prediction" target="_blank" title="The Art and Science of Prediction">As we discussed previously</a>, any numerical simulation is only as good as the modeling assumptions that underlie it. If engineers in the same team make different modeling choices then it becomes difficult to directly compare simulation results down the line.</p>
<p><strong>How do you ensure that methods developed in one part of your organization are deployed by engineers working elsewhere?</strong></p>
<p>To answer this question, CD-adapco has developed the Simulation Assistant, an interactive user interface that allows you to capture best practices and deploy them across your whole organization, ensuring repeatability of process and guaranteeing consistency of results.</p>
<p><a href="http://www.cd-adapco.com/sites/default/files/aero%20assistant.png" onclick="window.open('http://www.cd-adapco.com/sites/default/files/aero%20assistant.png','Aero Simulation Assistant','width=484,height=1047');return false;"><img src="/sites/default/files/aero%20assistant.png" alt="Simulation Assistant for Aero Post Processing" title="Aero Assistant" width="200" height="433" style="margin: 5px 8px; float: right;" /></a>The Simulation Assistant itself is exposed as a side panel within STAR-CCM+, subdivided into separate tasks to step you through your analysis workflow. You can execute actions within the simulation tree, set parameters or automatically execute complex series of tasks. Each task can be thought of as a mini, and interactive Java macro. Using the Simulation Assistant, you can execute entire workflows from geometry creation through to post-processing or simply automate small parts of your process, input recommended settings or easily handle sophisticated analysis setups.</p>
<p>The Simulation Assistant is also a valuable tool for introducing new or inexperienced engineers to your simulation process, allowing a tailored step-by-step approach that guides the engineer through each of the stages necessary to produce a simulation. Individual steps can be illustrated using pictures and actions are able to highlight the relevant areas in the STAR-CCM+ simulation tree, making for a visual and intuitive learning process.</p>
<p>In the early part of the learning experience you can expose the rookie engineer to only those parts of the software that are necessary to perform a specific task. However, as their experience and confidences grows, you can use the Simulation Assistant to expose more of the underlying detail. Even if you are an experienced user of STAR-CCM+, the Simulation Assistant can help you learn new applications to broaden your simulation capabilities.</p>
<p>The Simulation Assistant will be released as part of STAR-CCM+ v8.06 this fall. I'll be back then to provide you with some examples of Simulation Assistants that we've been testing internally, and to guide you through the steps for creating your own.</p></div></div></div><div class="field field-name-field-products field-type-taxonomy-term-reference field-label-above"><div class="field-label">Products:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="/products/star-ccm%C2%AE" typeof="skos:Concept" property="rdfs:label skos:prefLabel">STAR-CCM+®</a></div></div></div>Thu, 19 Sep 2013 09:36:07 +0000Joel Davison6266 at http://www.cd-adapco.com